This invention relates to a copying machine with automatic document feeding means and more particularly to a copying machine having an automatic document feeder which automatically detects the document size.
According to a previously considered method of detecting the size of a document to be copied by a copying machine, a plurality of sensors are provided on the document carrying table to detect both the longitudinal and transverse dimensions of the document. Another method has been to determine the size on the basis of the distance traveled by the document as it is transported to a copying position. The former method is disadvantageous, for example, when documents of different sizes are piled on the table because only the size of the largest document is detected and smaller documents may be copied on a disproportionately large copy paper. In other words, the operator will have to prearrange the documents to be copied in such a way that documents of the same size lie together. The latter method is disadvantageous because the selection of copy paper size and adjustment of magnification by moving a lens, for example, must be effected each time a new document is transported. Adjustments of such conditions for copying operation are time-consuming and this method can defeat the very purpose of using an automatic document feeder to shorten the time required for making copies.